An apparatus includes a display screen, an ambient light sensor disposed behind the display screen, and an electronic control unit. An integration time of the ambient light sensor is unsynchronized to a frame rate of the display screen. The electronic control unit is operable to control a brightness of the display screen based on a duty cycle of a PWM blanking signal, wherein at least one OFF time of the PWM blanking signal occurs fully within a first integration period of the ambient light sensor, and wherein at least one other integration period ON time of the PWM blanking signal occurs fully during an ON time of the PWM blanking signal. The electronic control unit is further operable to acquire samples of an output of the ambient light sensor, to identify a highest value and a lowest value from among a consecutive group of the samples, and to estimate a magnitude of an ambient light signal based at least in part on the highest value and the lowest value.
Legal claims defining the scope of protection, as filed with the USPTO.
2. The apparatus of claim 1 wherein the electronic control unit is operable to estimate the magnitude of the ambient light signal based also on a duration of an integration period of the ambient light sensor.
3. The apparatus of claim 2 wherein the electronic control unit is operable to estimate the magnitude of the ambient light signal based also on an OFF time of the PWM blanking signal.
4. The apparatus of claim 3 wherein the integration period of the ambient light sensor is less than or equal to a difference between an ON time of the PWM blanking signal and the delay before start of the next integration time of the ambient light sensor.
5. The apparatus of claim 3 wherein the integration time of the ambient light sensor is greater than a sum of the OFF time of the PWM blanking signal and the delay before start of the next integration time of the ambient light sensor.
6. The apparatus of claim 1 wherein the electronic control unit is further operable to adjust a brightness of the display screen based, at least in part, on the estimated magnitude of the ambient light signal.
8. The method of claim 7 wherein estimating the magnitude of the ambient light signal is based also on a duration of an integration period of the ambient light sensor.
9. The method of claim 8 wherein estimating the magnitude of the ambient light signal is based also on an OFF time of the PWM blanking signal.
10. The method of claim 9 wherein the integration period of the ambient light sensor is less than or equal to a difference between an ON time of the PWM blanking signal and the delay before start of the next integration time of the ambient light sensor.
11. The method of claim 9 wherein the integration time of the ambient light sensor is greater than a sum of the OFF time of the PWM blanking signal and the delay before start of the next integration time of the ambient light sensor.
12. The method of claim 7 including adjusting a brightness of the display screen based, at least in part, on the estimated magnitude of the ambient light signal.
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August 1, 2019
April 5, 2022
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